Shimano Dura Ace RD-R9100 Rear Derailleur

The Shadow design offers faster wheel changes thanks to the fact that it moves the derailleur out of the way of the dropouts. It also offers faster and more precise shifting than ever before. The R9100 derailleur only comes in one length and will work with cassette sprockets up to 30T. This means that the R9100 offers a greater rider tuned ratio than previous editions. The shadow design places the rear derailleur under the chainstay and cassette to give a slimmer profile, which not only improves aerodynamics but helps prevent damage in a crash.